Electric jack



W. R. G. ALTERS ELEGTRI C JACK Filed May a, '1924 s sheets-.sheet l Nov. 4 1924. LSYZ W. R. G. ALTERS ELECTRI C JACK Filed May 8, 1924 3 Sheets-Sheet 2 fi G. ALTERS EQECTRIC JACK May s, 12224 5 Sheets-Sheet 5 Patented Nov.. 4, 1924.

WILLIAM R. Gr. ALTERS, F JGHNSTOWN, PENNSYLVANIA.

ELECTRIC JACK.

Application led May 8, 1924. Serial No. '711,928.

' T0 all whom it 'may concern.'

Be it known that l, VVILLmM R. Gr. ALTERS, a citizen or' the United States, and resident of Johnstown, in the county of e Cambria and State of Pennsylvania, have invented certain new and useful Improvements in Electric Jacks, of whichithe following is a specification.

My invention relates particularly to portable electric jacks having a motor for operating the same, which motor can be driven from any suitable source of electric current. These jacks are particularly adapted to litt heavy objects but are mounted to be readily moved from one place to ano-ther in a machine shop.

An object of the invention is to provide a jack of the general character described which will be, simpleand efficient in conv struction and which will be' able to lift heavyweights by a relatively small amount of current. l

Another object is to provide simple means for automatically stopping the motor when the jack has reached the limit of its lifting movement.

Another object is to provide ready means for reversing the direction of movement as required, or stopping the movement at any desired point.

A further object is to provide in a single structure two movable jack members, one ot which will raisel the weight to a certain height whence it can be readily transferred to the other and raised an additional distance thereby.

`Further objects will be apparent from the following-detailed description and the appended claims. 4c ln the drawings:

Figure 1 is a side elevation of my device with a portion in section on the line 1-1 of Figure 2.

Figure 2 is a vertical section wlth parts 1n elevation taken on the line 2-2 of Figure 1.

Figure 3 is a top plan view.

VFigure i is a section on the line @L -l ot Figure 2.

Figure 5 is a detail View of the switch op- "l erating mechanism.

Figure 6 is a side elevation of a modiiication.

Figure 'i' is a detail view oft a hitting head in modification of Figure 6.

Figure 8 is a vertical section of a portion of the operating mechanism of the modification of Figure 6.

A suitable base 1 is mounted on wheels which are illustrated as castors 2 mounted to turn about horizontal and vertical axes @0 and thus permit the jack to be moved about as desired. Three wheels only are illustrated but a greater number may be used if rthesize orv shape of the base render it advisable. Mounted at one side of the base 1 isan elec @5 tric motor 3, the shaft of which is extended at one end and provided with a pinion 4. This meshes with a pinion 5 on a short shaft 6 mounted in bearings 7 and 8 fastened to the base 1. The shaft also carries a pinion .9 which meshes with a pinion 10 on a shaft 11 supported at its ends in the sides of the casing 12 rising from 4thebase 1, and near its middle by a support 13.

A casing 14 of generally circular shape is adapted to be fastened to the casing 12 and has a cylindrical upward extension 15 adapted to contain and guide the liftingl head 16 of the jack. This head has a igroove 17 in one side into which extends a pin 18 carried 30 by the casing 14, and thus longitudinal movement of the jack head is permitted whiie movement of rotation is prevented.

Held by splines 19 and 20 on the shaft y11 are two bevel gears 21 and 22 which are 'thus permitted sliding movement on the shaft, but are constrained to rotate therewith. Either of the gears 21 or 22 may be brought to mesh with a bevel gear 23 vfast on the lower end of a screw 24; the screw threaded portion of which is adapted to engage in a similar internally threaded portion of the jack head 16.

Obviously, if either' gear 21 or 22' meshes with the gear 23 and the motor is driven, the shaft 11 will rotate driving the screw 2li, and since the screw cannot move endwise and the jack head 16 cannot rotate, the rotation of the screw will move the jack head endwise, and thus perform the desired litt- 'ico ing operation.

sleeve 25 surrounding" fthe shaft 11 conn nects the two 2(gears 21 and 22 so that when either one is moved endwise, the other wiil move also. These gears are moved in the followinga manner: Pivotally mounted in lug 26 depending7 'from the inner portion the casing; 14: is a short lever 27 having avoids damage to the jack through any fail-v one end pin and slot connection 28 with a link 29 connected to a hand lever 30 extending outward through an opening in the casing. This lever is pivoted at 31 and has a I depending finger 32 bearing against the out.- side of the gear 21. Obviously a movementof the lever to the left. from the position shown in Figure 1 will move the gears 2l and 22 toward the right, disengage the gear 22 from the gear 23, and if the movement is continued far enough, mesh the gears 21 and 23. A link 33 is also attached to the lever 30, is bent to pass around the screw 24, passes through a suitable supporting eye 34 and has a depending linger 35 bearing against the ou-tside of the gear 22. A movement of the lever 30 in the opposite direction will therefore bring the gears 22 and 2 3 into mesh and disengage the gears 21 and 23. In `either case, stopping the movement of the handle lever 30 in mid position will hold both gears 21 and 22 disengaged from the y gear 23.

The motor and gearing is so arranged that when the parts are in the position shown in Figure 2, arotation of the shaft 11 will elevate the jack. When the gear 21 is shifted to engage the gear 23, a rotation of the shaft Will lower the jack. On this movement, near the end thereof, the lower portion 36 of the jack head will enga-ge the free end of the lever 27 and act to move the handle lever 30 to neutral position, thus disengaging the gears 21 and 23 and.` preventing damage to the device.

Sliding in bearings 37 fast in the side of the casing 14 is a rod 38 having an inturned end 39 passing through an opening 40 in the casing and working in a groove 41 in the jack head. The lower end of this rod 38 is connected to and readily detachable from a member 42 forming one element of a knife edge switch 43 located in the motor circuit 44. The member 42 is pivoted to the casing 14 and the portion 43 is carried thereby but insulated therefrom in any desiredz manner. When the jack is employed for lifting purposes, as the head nears 'its upper limit of movement, the lower'end of the groove 41 comes against the inturned yend 39 of the rod 38 raising the same., and thereby lifting the member 42 and' breaking the circuit, whereupon .the motor is stopped. This ure to stop the motor when the upper limit of movement of the jack head has been reached.

ln Figures 6, 7 and 8 l have illustrated-a form of viaclr which is modified in some respects. Parts'which are similar are designated by the same reference numerals as in the first form. The sleeve which is splined to the shaft 11 and connects the gea-rg3 21 and; is provided near its center with annular rings forming groove willi-oh engages the forked end 45 of a gear shifter 46 pivoted at 47 and having an outwardly eX- tending handle. A

Two bevel gears 48 and 49 are mounted in the same manner on the shaft 11 and moved to engage alternately with the bevel gear 51 by means of a gear shifter 50. The bevel gear 51 is fast upon the lower end of a screw member 52. The casing 53 in which the j aok head 16 slides, is provided with an offset 54 in the upper end of which the screw 52 is stepped. The lower end of the screw is supported by a plate 55 bolted or otherwise secured to the base. The jack head 56 is provided with an internally threaded passage 57 which engages the screw 52 and with a groove 58 which engages a correspondingly shaped rib 59 on the casing and prevents the jack head 56 from turning.

The jack `head 56 may be of the form shown in Fi ure 6 in which the upper por-A tion is the llfting portion, or it may have the form of Figure 7 in which the lifting portion is near the bottom, thus enabling this to be placed under objects lying .near

the'ground. When lused as illustrated in Figure 6, an object maybe lifted by the head 56 nearly to a level with the flat top of the oli'set 54 and the head 16 may be dropped to a point level with or slightly below this plane. The object then can be readily moved from the head 56 on to the table and thence to the head 16 for further lifting. A very compact structure can be obtainedin this manner.

Furthermore, an object can be simultaneously engaged if it has portions in two planes, by the heads 16 and 56, and by having the bevel Gears and screws of the same size, both heads will be lifted at the same speed. This is frequently a very useful feature.

In the form illustrated in Figures 1 to 5, the motor, gearing and the like may be inclosed by a cover plate 60.

lt is obvious that many details of the invention may be modified without departing from the spirit thereof, and that portions may be used without other parts thereof. It is accordingly to be understood that the invention is to be regarded as limited only by the scope of the appended claims.

l claim as my invention:

1. A jack comprising a base, an electric motor earried by said base, a casing carried by the base, a jack head slidable in said oasing, means whereby said jack head may be raised and lowered by the electric motor, a groove in the side of said jack head, an opening through the casing registering with the said groove, a slidable member having a linger extending through the opening and into said groove to be engaged by the end hereof, the opening in easing limiting the movement of the slidahle member in each direction and a switch in the motor circuit which is moved by the movement of-such slidable member.

2. A jack comprising a base, a motor driven shaft thereon, two jack heads mounted for` independent or simultaneous reciprocating movement upon said base, and gearing adapted to connect the shaft and jack heads to produce such movementas desired.

3. A jack comprising a base, a motor driven shaft thereon, two jack heads mounted for reciprocating movement upon said base, and gearingv adapted to connect the shaft and jack heads to produce either inde pendent movement in either direction, simultaneous movement in either direction, or movement of the two heads in opposite directions as desired.

4. A jack comprising a base, a motor driven shaft thereon, two jack heads mounted for reciprocating movement thereon, one adapted to take up the lifting movement where the other stops, and an intermediate supporting portion between the two'heads.

5.,A jack comprising a base, a motor driven shaft mounted thereon, two reciprocating jack heads mounted upon said base, screw means for driving each of said heads,

va pair of bevel gears for each screw carried on said shaft, and means for independent] operating each pair of gears to drive each shaft as desired.

In testimony whereof, I 4have hereunto subscribed my name.

WILLIAM R. G. ALTERS- 

